1. Field of the Invention
The present invention relates to a new intestinal microflora-improving agent.
2. Description of the Related Art
It is said that there are about 100 trillion intestinal bacteria in the human intestines. These are classified into over 300 kinds. The significance of the intestinal microflora in humans has been revealed. For example, a fundamental investigation on relationships between intestinal bacteria and aging of the host has revealed that intestinal bacteria influence the activities of enzymes in various organs and the metabolism of important substances and that intestinal bacteria depress the accumulation of lipids and the inactivation of the detoxification function of the liver with aging (See Yazawa, K. et al. Mech. Ageing Devel. 17, 173 (1981), Kawai, Y. et al. Mech. Ageing Devel. 16, 149 (1981), Kawai, Y et al. Infect. Immun. 19, 771 (1978), and Kawai, Y am. J. of Clin. Nut 32, 187 (1979)). Many other studies on the importance of the intestinal microflora in hosts have been reported. (See Freter, R. Am. J. Clin. Nutr. 27, 1049 (1974), Gorbach, S. L. Gastroenterology, 60, 1110 (1971), Savage, D. C. Am. J. Clin. Nutr. 25, 1372 (1972), de Dombal, F. T., et al. Gut, 10, 270 (1969), Donaldson, R. M., Jr. New Engl. J. Med., 270, 938 (1964), Gordon, H. A., et al. Bacteriol. Rev., 35, 390 (1971), Taniguchi, T., et al. Microbiol. Immunol., 22, 793 (1978), Elyssen, H., Proc. Nutr. Soc., 32, 59 (1973), Wostmann, B. S. et al. J. Germfree Life Gnotobiol., 5, 4 (1975), Phear, E. A., et al. Br. J. Exp. Pathol., 37, 253 (1965), and Wolpert, E. et al. Lancet, ii, 1387 (1971)).
As evidenced by these studies, in many cases, the host's health is deteriorated by the abnormal over-growth of harmful bacteria in the intestines. On the contrary, it is kept in a normal condition or is improved by the ordinary growth of useful intestinal bacteria such as Streptococcus, Lactobacillus, and Bifidobacterium. These facts strongly suggest that the selective growth of such useful intestinal bacteria in the intestines is quite important for the prevention and treatment of various kinds of so-called middle-aged or geriatric diseases.